A low-emissivity glass refers to a glass in which a low-emissivity layer containing a highly reflective metal in an infrared region such as silver (Ag) is deposited as a thin film. The low-emissivity glass is a functional material having an energy saving effect of a building structure by reflecting radiant rays in the infrared region to block outdoor solar radiant heat in summer and to preserve indoor heating radiant heat.
Silver (Ag) used for the low-emissivity layer is oxidized when being exposed in the air, such that dielectric layers are deposited as oxidation prevention layers on an upper part and a lower part of the low-emissivity layer.
In general, the low-emissivity layer should be formed at a specific thickness or more in order to decrease emissivity in the low-emissivity coating, and accordingly, there is a problem in that visible light transmittance is decreased, which reduces a lighting property.